Recovery of oil from tar sands using high water content oil-external micellar dispersions

ABSTRACT

OIL FROM TAR SANDS IS EXTRACTED BY CONTACTING THE TAR SANDS WITH AN OIL-EXTERNAL MICELLAR DISPERSION (CONTAINS 55-90% WATER), THEREAFTER THE SANDS ARE SEPARATED FROM THE MICELLAR SOLUTION CONTAINING SOLUBILIZED OIL, AND THEN THE OIL IS RECOVERED FROM THE MICELLAR DISPERSION. THE MICELLAR DISPERSION CAN BE AT A TEMPERATURE IN EXCESS OF 100*F. AND THE PH OF THE WATER WITHIN THE DISPERSION CAN BE ABOUT 7-14. VOLUME AMOUNTS OF 0.5-30 VOLUMES OF MICELLAR DISPERSION PER VOLUME OF TAR SAND ARE USEFUL WITH THE PROCESS.

United States Patent Office 3,660,268 Patented May 2, 1972 3,660,268 RECOVERY OF OIL FROM TAR SANDS USING HIGH WATER CONTENT OIL-EXTERNAL MICELLAR DISPERSIONS Joe T. Kelly, deceased, late of Littleton, Colo., by La Verne S. Kelly, executrix, and Fred H. Poettmann, Littleton, C010,, assignors to Marathon Oil Company, Findlay, Ohio No Drawing. Filed Dec. 29, 1969, Ser. No. 888,900

Int. Cl. C10g 1/04 US. Cl. 208-11 13 Claims ABSTRACT OF THE DISCLOSURE Oil from tar sands is extracted by contacting the tar sands with an oil-external micellar dispersion (contains 55-90% water), thereafter the sands are separated from the micellar solution containing solubilized oil, and then the oil is recovered from the micellar dispersion. The micellar dispersion can be at a temperature in excess of 100 F. and the pH of the water within the dispersion can be about 7-14. Volume amounts of -30 volumes of micellar dispersion per volume of tar sand are useful with the process.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the recovery of hydrocarbon from mined tar sands by contacting the sands with an oil-external micellar dispersion (contains 55-90% water) to solubilize the hydrocarbon from the tar sands, thereafter separating the micellar dispersion containing the solubilized hydrocarbon from the tar sands and then recovering the solubilized hydrocarbon from the micellar dispersion. The micellar dispersion contains hydrocarbon, surfactant and aqueous medium, and optionally cosurfactant and/or electrolyte. The mined tar sands are preferably comminuted before being contacted with the micellar dispersion.

Description of the prior art Tar sands, also known as oil sands and bituminous sands, are sands which contain a very viscous oil. The viscosity is substantially higher than the viscosity of conventional crude oil obtained from sandstone. Due to this high viscosity, inter alia, the techniques used in the recovery of the lower viscosity crude oil from sandstones are not adaptable to the recovery of oil from tar sands.

US. 2,882,973 to Doscher et al. teaches the recovery of oil from tar sands by contacting the tar sands in situ with an aqueous solution having a pH of about 12 and containing a non-ionic surfactant.

US. 1,497,607 teaches the recovery of oil from comminuted tar sands 'by contacting the sands with steam. The steam aids in separating the oil from the tar sands. The lower specific gravity of the oil results in the oil forming on top of a water layer while the sand settles to the bottom.

US. 3,050,289 to Gerner teaches the use of superheated steam to strip oil from tar sands. Gerner first directs a high pressure jet stream of solvent, e.g. naphtha, kerosene, or gas oil, at a tar sand deposit in a pit to leach the tar sands, thereafter the solvent plus tar sand mixture is conveyed to a kiln wherein superheated steam (up to 700 F.) is countercurrently passed over the tar sands to strip out the solvent and the oil.

SUMMARY OF THE INVENTION Applicants have discovered that oil from tar sands can be recovered by contacting the tar sands with an oilexternal micellar dispersion containing about 55-90% water. The micellar dispersion solubilizes at least a portionof the oil from the tar sands. Thereafter, the micellar dispersion containing the solubilized oil is separated from the sands and the oil recovered from the dispersion. The tar sands are preferably comminuted and optionally can be heated before coming in contact with the micellar dispersion. Also, the micellar dispersion is preferably at a temperature about about 100 F.-l50 F. After the contacting step, the micellar dispersion containing the solubilized oil can be diluted with a low viscosity hydrocarbon, e.g. kerosene, gasoline, etc. to facilitate movement of the micellar dispersion, e.g. downstream, where the oil is separated from the micellar dispersion. The spent tar sands are separated from the micellar dispersion with the aid of gravity forces, centrifugal forces, heat, etc.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The micellar dispersion useful with this invention is oil-external and contains about 55 to about aqueous medium. Also, the micellar dispersion contains hydrocarbon, surfactant, and optionally cosurfactant and/or electrolyte. Examples of volume amounts include about 4% to about 40% hydrocarbon, about 55% to about 90% aqueous medium, at least about 4% surfactant, about 0.01% to about 20% cosurfactant, and about 0.001% to about 5% by Weight of electrolyte. The micellar dispersion can contain other additives such as corrosion inhibiting agents, sequestering agents, etc.

Examples of useful hydrocarbons include crude oil, partially refined fractions of crude oil and refined fractions of crude oil. Specific examples include side cuts from crude oil columns, crude column overheads, straight-run gasoline, liquefied petroleum gases, etc. Also, synthesized hydrocarbons are useful.

The aqueous medium can be soft water, brackish water, or brine Water. Preferably, the water is one that is compatible with the particular tar sands and where the water contains ions, these ions are preferably compatible with the ions within the tar sands.

Surfactans useful with the micellar dispersions include nonionic, cationic, and anionic surfactants. Specific examples include those surfactants taught in US. 3,254,714 to Gogarty et al. Also useful are surfactants such as Duponol WAQE (a 30% active sodium lauryl sulfate marketed by Du Pont Chemical Corporation, Wilmington, Del.), Energetic W- (a polyoxyethylene alkylphenol marketed by Armour Chemical Co., Chicago, 111.), Triton X-100 (an alkylphenoxy polyethoxy ethanol, marketed by Rohm & Haas, Philadelphia, Pa.), Arquad 12-50 (a 50% active dodecyl trimethyl ammonium chloride marketed by Al'- mour Chemical Co., Chicago, Ill.), and like materials. Preferably the surfactant is a petroleum sulfonate, also known as alkylaryl naphthenic sulfonate. The sulfonate can contain a monovalent cation and can have an average equivalent weight within the range of about 350 to about 520 and more preferably about 400 to about 470. The surfactant can be a combination of low, medium, and high average equivalent Weight surfactants or sulfonates or mixture of any two or more surfactants.

The cosurfactant (also defined as cosolubilizer and semi-polar organic compound) can have limited water solubility as well as infinite water solubility. Examples of preferred cosurfactants include alcohols, amino compounds, esters, aldehydes, ketones, and like materials containing from one up to about 20 or more carbon atoms and more preferably about 3 to about 16 carbon atoms.

holic liquors such as fusel oil, and like materials. In general, primary, secondary, and tertiary alcohols are useful. Preferably the cosurfactant is present in concentrations of about 0.01 to about 5.0% by volume. Mixtures of two or more different cosurfactants are also useful.

Electrolytes useful with the micellar dispersion include inorganic bases, inorganic acids, inorganic salts, organic bases, organic acids, and organic salts which are strongly or weakly ionized. Preferably, the electrolyte is inorganic base, inorganic acid or inorganic salt, and more preferably is inorganic base. Specific examples of preferred electrolytes include sodium hydroxide, sodium chloride, sodium sulfate, hydrochloric acid, sulfuric acid, sodium nitrate, and like materials. Other specific examples include those taught in US Pat. No. 3,330,343 to Tosch et al. Where a high pH of the water within the oil-external micellar dispersion is desired, the electrolyte is preferably an inorganic base such as sodium hydroxide, e.g., a pH up to about 14 can be obtained using sodium hydroxide. Also, it is preferred that the electrolyte be compatible with the other components within the micellar dispersion as well as the ions within the tar sands.

It is desired that the pH of the water within the micellar dispersion be from about 7 to about 14. Preferably, the pH is above about 10 and most preferably about 12. Generally, higher pHs facilitate solubilization of the oil.

The tar sands are preferably comminuted before being contacted with the micellar dispersion. Such will facilitate contacting the tar sands with the micellar dispersion and solubilizing the oil from the tar sands. However, if the tar sand is not comminuted, it will merely take longer to effect sufiicient solubilization of the oil. In addition, the tar sand can be heated to facilitate solubilization of the oil from the tar sands. Temperatures in excess of 100 F. and preferably in excess of 150 F. are useful.

Volume amounts of from about 0.05 to about 30 volumes of the micellar dispersion per volume of tar sand are useful in the contacting step. More preferably about 0.1- volumes of micellar dispersion per volume of tar sand is useful. The particular volume ratio of micellar dispersion to volume of tar sand will depend on the economics, i.e. the rate of return, and the degree of extraction of the oil from the tar sands, etc.

Agitation may be beneficial in the contacting step, i.e. where the micellar dispersion contacts the tar sands. The contacting can be effected in a vessel which can optionally be pressurized, and heat can be applied to the vessel. It is preferred that the tar sands and dispersion be efiiciently mixed so that efficient solubilization of the oil out of the tar sands can be effected. Agitation by motorized stirrers, vibration, etc. are useful.

The resulting mixture of micellar dispersion containing solubilized oil is separated from the spent tar sands. It may be advantageous to decrease the viscosity of the micellar dispersion containing the solubilized oil before separation, e.g. if the viscosity is within the range of 50050,000 cp. at ambient temperature, it may be desirable to add a diluent to reduce the viscosity to 30-1000 cp. Any diluent that will effectively reduce the viscosity of the micellar dispersion and is compatible with the dispersion is useful, examples of diluents include kerosene, gasoline, lower molecular weight hydrocarbons, etc.

Separation of the spent tar sands from the micellar dispersion containing the solubilized oil can be by classification, gravity separation, centrifugal separation, and other means known in the art. Also, part of the spent tar sands containing residual but feasible quantities of oil can be recycled back to the process for contacting with micellar dispersion to effect solubilization of this retained oil. Recycling certain streams of the process, effecting mixing and heating of certain streams within the process, etc. are useful and obvious to those skilled in the art.

As mentioned earlier, the micellar dispersion can be heated to a temperature in excess of 100 F. and preferably in excess of 150 F. to facilitate solubilization of the oil out of the tar sands. When such is desirable, the micellar dispersion should be designed to maintain its thermostability throughout the heating cycle and at the temperature of usage. For example, if the micellar dispersion is to be used at a temperature in excess of 150 F. the molecular weight of the surfactant and/or cosurfactant, the molar ratio of the surfactant to the hydrocarbon can be increased, the electrolyte content within the micellar dispersion can be increased, etc. to impart thermostability to the micellar dispersion at higher temperatures. Examples of methods to increase the thermostability range of micellar dispersions to higher temperatures are taught in US. Pats. Nos. 3,493,048 to Jones, 3,493,047 to Davis et al., 3,495,660 to Davis et al., 3,500,912 to Davis et al. and 3,508,611 to Davis et al.

The micellar dispersion containing the solubilized oil is further processed to recover the oil from the micellar solution. In certain cases, especially where the micellar dispersion has been designed to have a high temperature thermostability but does not have thermostability at lower temperatures, the temperature of the resulting mixure can be lowered to obtain phase separation; in this case the oil from the tar sands will be in the top phase. Where the latter occurs, the top phase can be decanted from the mixture to obtain the oil from the tar sands. The bottom phase, being mostly water soluble components and some oil soluble components, can be recycled back to the contacting stage and, before entering the contacting stage, it can be adjusted with the necessary and desired components to obtain a micellar dispersion having the desired thermostability range at the temperature used in the contacting step.

Examples of useful oil-external micellar dispersions useful with this invention can be found in US. Pat. No. 3,497,006 to Jones et al.

It is not intended that the specifics taught herein limit the invention. Rather, all equivalents known or obvious to those skilled in the art are intended to be incorporated within the scope of the invention as defined within the specification and appended claims. Unless otherwise specified, all percents are based on volume.

What is claimed is:

1. A process for recovering oil from tar sands comprising contacting the tar sand with sufficient oil-external micellar dispersion, the dispersion containing about 55 to about water, to solubilize at least a portion of the oil within the tar sands, separating the sands from the micellar dispersion containing the solubilized oil, and recovering the oil from the micellar dispersion.

2. The process of claim 1 wherein the micellar dispersion is at a temperature in excess of about F.

3. The process of claim 1 wherein from about 0.05 to about 30 volumes of the micellar dispersion per volume of the tar sands are used to contact the tar sand.

4. The process of claim 1 wherein from about 0.1 to about 15 volumes of the micellar dispersion per volume of tar sand are used to contact the tar sand.

5. The process of claim 1 wherein the water within the micellar dispersion is at a pH of about 7 to about 14.

6. The process of claim 1 wherein the water within the micellar dispersion is at a pH of about 12.

7. The process of claim 1 wherein the micellar dispersion contains about 55 to about 90% aqueous medium, at least about 4% surfactant, and about 4% to about 40% hydrocarbon, the percents based on volume.

8. The process of claim 7 wherein the micellar dispersion contains about 0.01% to about 20% by volume of cosurfactant, or about 0.001% to about 5% by weight of electrolyte, or about 0.01% to about 20% by volume of cosurfactant and about 0.001% to about 5% by weight of electrolyte.

9. The proces of claim 1 wherein sufficient hydrocarbon diluent is mixed with the micellar dispersion containing the solubilized oil to reduce the viscosity to about 30 to about 1000 cp. at ambient temperature.

10. The process of claim 1 wherein the micellar dispersion contains a petroleum sulfonate having an average equivalent weight within the range of about 350 to about 520.

11. A process for recovering hydrocarbon from mined tar sands comprising contacting the tar sands with sufficient amounts of an oil-external micellar dispersion comprised of at least about 4% by volume of a petroleum sulfonate, 55 to about 90% by volume aqueous medium, and about 4% to about 40% by volume hydrocarbon, to solubilize at least a portion of the hydrocarbon within the tar sands, separating the tar sands from the micellar dispersion containing the solubilized hydrocarbon, and then recovering the solubilized hydrocarbon from the micellar dispersion.

12. The process of claim 11 wherein the petroleum 6 sulfonate has an average equivalent weight within the range of about 350 to about 520.

13. The pro' cess of claim 11 wherein the micellar dispersion conta'itis about 0.01 to about 20% by volume of cosurfactant 'and about 0.001% to about 5% by weight of electrolyte.

References Cited UNITED STATES PATENTS 2,921,010 1/ 1960 sherborne "208-11 3,542,666 11/1970 Simpson .a 20811 2,911,349 11/1959 Coulson 20811 3,331,765 7/1967 Canevari et a1 208-l1 3,392,105 7/1968 Poettmann et a1 208-11 15 CURTIS R. DAVIS, Primary Examiner 

